Generally, the only time customers need to upload files to a webshop is when they place an order for something.

For example:

If I sell T-Shirts with printed graphics on them, and I want my customers to send me a picture that they want on the T-Shirt, then they can only send me the image when they are placing their order.

If you allow people to freely send files (including images), then you risk opening up security issues as well as people flooding your server with unnecessary rubbish.

The UPLOAD file feature is controlled in the ATTRIBUTES function. Files that a customer UPLOADS with an order are stored in the images/uploads folder. Uploads are identified by the filename being the same as the customer's order number.